The fight against climate change is being used by the government to regain the public's confidence in politics, the business secretary Lord Mandelson said today.

"We are at a precarious time for mainstream politics in the UK. We can get cynical about politics in this country, or we can have a serious debate about what needs to be done to get our politics back on track and our economy back to growth," he said in a speech at the Policy Network event at the London School of Economics.

"A positive politics of climate change depends on us deciding that politics works, that it is how we focus collectively on a different future, and in focusing on it, make it happen."

He said that everyone has to change their attitude to climate change politics. "Mainstream climate-change politics obviously can't be totally anti-politics, anti-business and anti-growth. We can't just throw green slime at the problem," he said, referring to an incident this year when an environmental protester threw a cup of green custard at him.

Mandelson said the government has a responsibility to ensure that UK-based companies are equipped to compete for the new demand created by climate-change policies. "Almost 900,000 people already work in the sector or its supply chain in the UK, not just in green manufacturing but in green services like consultancy or low-carbon venture capital. The sector is projected to maintain positive growth rates, even through the downturn. We are in a strong position to be a global first mover."

He argued that the government needs to develop a long-term strategic approach to help the low-carbon industry. "Up until recently there has been too much ambiguity or uncertainty in UK climate policy – in nuclear energy or renewables, for example. Clear leadership on these questions over the course of the last year has now unlocked billions of pounds of investment in UK capacity. We need to get that sense of clear strategic direction right through our action as a government."